<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<!--双向绑定-->
<div id="app">
<input type="text" v-model="message">{{message}}
</div>

<!--导入Vue.js-->
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>

<script>

    var app = new Vue({
        el: '#app',
        data: {
            message: "123"
        },

    })
</script>

</body>
</html>